Effect of a revolved wedge strut induced mixing enhancement for a hydrogen fueled scramjet combustor

The mixing concept of fuel and air is the burning issue for hypersonic vehicles (scramjet) due to the less resident time of supersonic air in the combustion chamber. So far, significant research has been done for mixing enhancement and introduced different technologies; still, there is a lack of research for mixing improvement. Shock wave and shear mixing layer are the main parameters for investigating mixing criteria at supersonic speed. In this research, an innovative fuel injection strut has been designed to develop mixing enhancement by elevating multiple interactions between the shock wave and shear mixing layer. This new strut has been designed with the reference of the DLR scramjet combustor. From the reference of a wedge-shaped strut, a revolved (wedge shape – circular 3D) wedge strut has been modeled with the same fuel injection base points. This new strut's performance has been analyzed for mixing enhancement by visualizing the development of shock wave, shear-mixing layer, and their interactions. Three-dimensional numerical analysis has been carried out by solving the Reynolds-Averaged and Navier-Stokes (RANS) equations. A comparison of results has been made for the basic wedge and new strut and identified the increase in multiple interactions of the shock wave and shear layer, which leads to an increase in mixing enhancement. For the new strut, complete mixing has been achieved within a distance of 0.180 m with an average increase in mixing efficiency of 9% and increased pressure losses of 12%.     

Impact of multi threshold transistor in positive feedback source coupled logic (PFSCL) fundamental cell

Analog Integrated Circuits and Signal Processing - In this paper, a new fundamental cell in positive feedback source coupled logic is presented, which is an improvement over the existing...     

Correction to: Recent Deep Learning Techniques,Challenges and Its Applications for Medical Healthcare System: A Review

Neural Processing Letters - A correction to this paper has been published: https://doi.org/10.1007/s11063-021-10527-5     

Modeling Fischer–Tropsch kinetics and product distribution over a cobalt catalyst

A detailed kinetic model describing the consumption of key components and product distribution in the Fischer–Tropsch synthesis (FTS) over a 20%Co/0.5Re γ-Al₂O₃ commercial catalyst is developed. The developed model incorporates the H₂O-assisted CO dissociation mechanism developed by Rytter and Holmen and a novel approach to product distribution modeling. The model parameters are optimized against an experimental dataset comprising a range of process conditions: total pressure 2.0–2.2 MPa, temperature 210–230°C, CO conversion range of 10%–75% and feed with and without added water. The quality of the model fit measured in terms of mean absolute relative residuals (MARR) value is 23.1%, which is comparable to literature reported values. The developed model can accurately describe both positive and negative effects of water on the rate kinetics, the positive effect of water on the growth factor, temperature and syngas composition on the kinetics and product distribution over a wide range of process conditions, which is critical for the design and optimization of the Fisher–Tropsch reactors.     

Impact of Chitosan-Prunus cerasoides gum exudates on the thermal properties,storage stability and antioxidant activity of anthocyanins from Berberis lycium Royle

For the protection of anthocyanins from berries of Berberis lycium Royle, the freeze dried microencapsulation method was used in five different combinations of chitosan (CH), Prunus cerasoides gum exudate (PG) and galactomannan as wall material with anthocyanin (ANS) as core material. The microencapsulated powders with different proportions of wall material showed encapsulation efficiency in the range of 90.51%–94.60%. Fourier-transform infrared spectroscopy confirmed the cross-linking interactions between ANS and wall materials. Enhanced thermal stability of the ANS with wall materials was indicated by thermogravimetric analysis. The stability of microcapsules and ANS was evaluated by spectrophotometric and liquid chromatographic methods at two conditions (4 °C and room temperature) during 90 days. The results revealed that ANS encapsulated with CH-PG/ANS (4/1) exhibited maximum retention of anthocyanins (72.88% and 60.02%) and enhanced the stability and antioxidant potential of anthocyanins.     

Understanding stability relationships among three curcumin polymorphs

Understanding thermodynamic stability relationship among polymorphs of any active pharmaceutical ingredient (API) is a necessary step for drug formulation development. Knowledge of such relationship enables identification of a stable polymorphic form at the prevalent conditions. Curcumin, a pharmaceutically active ingredient found in herbal spice turmeric, exists in three polymorphic forms; a monoclinic form (Form 1) and two orthorhombic forms (Form 2 and Form 3). However, thermodynamic stability relationships among curcumin polymorphs have not been ascertained yet. This work therefore, was focused on understanding thermodynamic stability relationships among curcumin polymorphs. During purification of curcumin, the pressure applied for vacuum evaporation of organic solvent was found to significantly affect the polymorphic outcome. Form 1 was obtained at pressures ranging from 300 to 400?mbar whereas Form 2 was obtained at pressures ranging from 100 to 200?mbar. Form 3 was obtained by liquid antisolvent precipitation using ultrasound and Bovine Serum Albumin (BSA) as an additive. The obtained polymorphs were characterized by X-ray diffraction (XRD) and Differential Scanning Calorimetry (DSC) techniques. Relative stability of polymorphs was established by conducting solvent mediated transformation studies, thermal analysis through DSC and variable temperature X-ray diffraction studies (VT-XRD). It was observed that Form 2 and Form 3 irreversibly convert to Form 1 upon heating. Further, Form 2 and Form 3 convert to Form 1 in aqueous organic solutions at temperatures ranging from 0?°C to 50?°C. Thus, the curcumin polymorphs were found to be monotropically related to each other with the monoclinic form (Form 1) being the most stable form.     

A Technique with Low Memory and Computational Requirements for Dynamic Tracking of Quantiles

Journal of Signal Processing Systems - A technique for dynamic tracking of quantiles of data streams, without storage and sorting of past data samples, is presented. It updates the quantile...     

Heuristic and Statistical Power Estimation Model for FPGA Based Wireless Systems

Wireless Personal Communications - As the technology is advancing day by day, the need of high performance devices is also increasing. High performance is achieved at the expense of high power...     

Performance Analysis and FPGA Prototype of Variable Rate GO-OFDMA Baseband Transmission Scheme

Wireless Personal Communications - To fulfill the increasing demand for high speed Variable Bit Rate (VBR) broadcast services with reliable Quality of Service, Group Orthogonal-Orthogonal Frequency...     

Influence of residual stress on performance of AlN thin film based piezoelectric MEMS accelerometer structure

Microsystem Technologies - The presence of residual stress is inevitable and major constraint for MEMS devices as they induce deformation, fracture, fatigue and micro structural changes in the...